sgp4

This Python package computes the position and velocity of an earth-orbiting satellite, given the satellite’s TLE orbital elements from a source like Celestrak. It implements the most recent version of SGP4, and is regularly run against the SGP4 test suite to make sure that its satellite position predictions agree to within 0.1 mm with the predictions of the standard distribution of the algorithm. This error is far less than the 1–3 km/day by which satellites themselves deviate from the ideal orbits described in TLE files. This package compiles the verbatim source code from the official C++ version of SGP4. You can call the routine directly, or through an array API that loops over arrays of satellites and arrays of times with machine code instead of Python.